When designing high efficiency compressors, it is important to provide relatively unrestricted suction gas flow to the compressor. This compressor suction process results in the generation of substantial noise due both to the rapid flow of suction gas into the compressor as well as the operation of the intake valving. Accordingly, it is desirable to provide some form of noise attenuating means in the suction gas flow path. When providing this noise attenuating means it is also important to overall compressor efficiency, as mentioned above, to insure a relatively free unrestricted flow of suction gas to the compressor. Accordingly, the use of various baffles and forms of restrictions in the main flow path is undesirable in that these device may create excessive flow losses requiring larger conduits to be utilized to prevent compressor suction starvation.
Currently, design parameters require the compressor to be as compact as possible, thus limiting the available space within the assembly for a suction muffler. This limited available space imposes several constraints on the physical size of the suction mufflers. Further, because of these space limitations, it is often necessary to extend the suction gas conduit in close proximity to the compressor's discharge muffler and the compressor's discharge conduits. Accordingly, as the discharge gas is relatively hot due to the compression process, the transfer of heat from the discharge gas to the suction gas can occur. It is desirable to minimize this heat transfer to the suction gas so as to maintain a high volumetric efficiency.
Accordingly, the present invention provides a refrigerant compressor having an improved suction gas muffler which effectively attenuates noise generated from the above-mentioned sources while still enabling relatively free unrestricted flow to the compressor. The suction gas muffler of the present invention is of the side branch type and comprises a relatively large diameter conduit having a housing secured thereto which defines a pair of side branch chambers each of which may be tuned to a different fundamental frequency. A pair of longitudinally spaced openings provide communication with each of the respective chambers and serves to define an impedance tube therebetween which may be tuned to attenuate a third fundamental frequency. Integrally formed baffles and ribs within each of the chambers further aid in noise attenuation by eliminating standing waves within the chambers as well as enhancing the rigidity of the muffler. The muffler is preferably fabricated from a polymeric composition so as to minimize heating of the suction gas being supplied to the compressor. Further, the use of such polymeric materials enables the suction conduit and muffler to be very inexpensively fabricated by suitable forming means such as, for example, injection molding.
The suction muffler is mounted to the motor cover using a twist lock design which incorporates a novel formed-in ring which creates a lip seal between the motor cover and the suction muffler. This integral sealing ring eliminates the need and associated costs of having an O-ring and snap-on sleeve mounting system common to assignee's prior art design as shown in assignee's U.S. Pat. No. 5,129,793.
Other advantages and objects of the present invention will become apparent to those skilled in the art from the subsequent detailed description, appended claims and drawings.